1. FIELD OF THE INVENTION
The present invention relates to a pressure gauge which is mounted to a vehicle's wheel and continuously displays the air pressure in the pneumatic tire forming part of the wheel.
2. DESCRIPTION OF THE PRIOR ART
When using the air hose at a service station, motorists often find that the pressure gauge incorporated into the air hose is inoperative and that they have forgotten to bring their pocket tire pressure gauge with them. In such situations, the motorist is left without a reliable means for ascertaining whether his or her tires are properly inflated, thus exposing the motorist to the potential hazards such as loss of control due to under inflation, tire blowout, poor fuel economy, and excessive tire wear associated with improperly inflated tires.
To remedy this problem tire gauges that permanently attach to the vehicle's wheels have been proposed in the prior art. However, none of the references cited below are seen to teach or suggest the pressure gauge of the present invention which remains on the vehicle's wheel during operation, and includes a pressure indicating member disposed in a tube having a transparent window and an opening in the tube which allows open fluid communication between the interior of the tire and the interior of the tube.
U.S. Pat. No. 1,495,553, issued to Durham, shows a tire gauge which is incorporated into the tire inflating apparatus. The Durham device does not display tire pressure, but rather shuts off air supply when the tire pressure reaches a preset level.
U.S. Pat. No. 3,720,224, issued to Foxhall, shows a valve stem cap having a tire gauge. The Foxhall device does not display pressure continuously and must be pressed in by the user to give a pressure reading.
U.S. Pat. No. 3,907,461, issued to Bouder, shows a hand air pump having a built in pressure gauge. Bouder does not show a gauge for continuously displaying tire pressure.
U.S. Pat. No. 4,310,014 issued to Parker, shows a valve stem with a built in pressure gauge. In the Parker device the bleeder valve is supported by an extensible sleeve which allows the bleeder valve to protrude farther away from the base of the valve stem when the tire pressure is increased.
U.S. Pat. No. 4,411,302, issued to Kuypers, shows one type of conventionally used valve stem.
U.S. Pat. No. 4,966,035, issued to Huang, shows a pocket type pressure gauge.
U.S. Pat. No. 5,307,846, issued to Heinemann, shows a device for equalizing the pressure in all four tires of a motor vehicle.
U.S. Pat. No. Des. 156,807, issued to Battersby, shows the ornamental design for a pocket type pressure gauge.
United Kingdom Patent Document Number 925,611, by Gfoell, shows a valve stem cap with an integral pressure gauge. The pressure gauge of Gfoell has a sliding member which protrudes above the open end of a tube to allow the tire pressure to be ascertained by a user.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.